Lasers and other electronic equipment generate waste heat during operation. At higher power levels typically required for industrial operation, removal of this waste heat is important to avoid temperature increases that could otherwise degrade the performance of the electronic equipment and related apparatus. A conventional method for disposing of waste heat is to blow ambient air over the heat-generating components and to exhaust the heated air through a room air conditioning system. In some controlled environments, e.g. clean room facilities for microelectronic circuit processing, it is not acceptable to exhaust heated air into the facility. At higher power levels, a separate exhaust system for heated air may also be inadequate to prevent overheating of components. A common alternative is to blow heated air in a recirculating air flow loop through an air-to-liquid heat exchanger, which transfers the heat from flowing air to a flowing heat transfer liquid, e.g. water. The heat is then carried away in the flowing liquid, and the cooled air is returned to be blown again over the heat-generating components.
Recirculating systems using heat exchangers usually require ducting to route the air through a heat exchanger instead of around it. However, if the components to be cooled involve multiple ventilation grilles and openings, it is difficult to design a duct that will seal around every opening, especially with multiple components. Additionally, water cooling adjacent to high voltage equipment often carries a risk of water leakage onto high voltage components, leading to short circuit, catastrophic equipment breakdown, and electric shock hazards. This is of particular concern if the equipment requires periodic access, disassembly, and/or reassembly for maintenance and/or component replacement, involving disconnecting and reconnecting water lines.
FIG. 1 is an isometric view of a conventional forced air cooled electronic enclosure 102 for laser or other equipment. In a typical recirculating air cooled system, a heat exchanger 104 is mounted inside a duct 106. The interface between duct 106 and heat exchanger 104 is gasketed, and duct 106 is configured to direct a recirculating air flow 108 entirely through heat exchanger 104, such that recirculating air flow 108 does not bypass heat exchanger 104. Typically a blower 110 is also mounted in flow series with heat exchanger 104 inside of duct 106 to propel recirculating air flow 108 through duct 106 and heat exchanger 104. An air inlet 112 and an air outlet 114 of duct 106 are connected to enclosure 102, forcing recirculating air flow 108 through the interior of enclosure 102.
Enclosure 102 typically contains heat-generating components (not shown). If these components are not cooled, temperature will build up in the interior of enclosure 102, leading to performance degradation or component failure. In the arrangement of FIG. 1, heat from heat-generating components within enclosure 102 is transferred to recirculating air flow 108, which in turn delivers the heat to heat exchanger 104. Typically heat exchanger 104 has a conventional finned tube structure, facilitating heat transfer from recirculating air flow 108 to water or other liquid coolant flowing through the tubes of heat exchanger 104. Heated recirculating air flow 108 enters heat exchanger 104 through air inlet 112 and duct 106, and cooled recirculating air flow 108 exits heat exchanger 104 and enters enclosure 102 through duct 106 and air outlet 114. Cool water or other liquid coolant enters heat exchanger 104 through a water inlet 116, and heated water or other heat transfer liquid exits heat exchanger 104 through a water outlet 118. For efficient cooling, it is important for air inlet 112 and air outlet 114 to be located such that recirculating air flow 108 passes over all heat-generating components within enclosure 102.
Particularly in industrial applications, it is important to minimize the manufacturing space occupied by electronic equipment. Thus it is important that such equipment be as compact as possible. Additionally, such manufacturing equipment typically requires periodic maintenance or component replacement. For required maintenance and/or component replacements, it is important to minimize the equipment down-time. Therefore it is desirable to facilitate access to internal components in a compact and often congested configuration with minimal disassembly and reassembly. In accordance with the conventional art, this often requires a design compromise between compactness and access. Complex and bulky cooling ducts consume valuable manufacturing floor space and often interfere with access to equipment components.
Needed in the art is a compact heat transfer method that provides cooling for multiple components without bulky or complicated ducting, and that permits easy access for maintenance and component replacement. Further needed in the art is a heat transfer method that allows water cooling of high voltage power equipment without danger of water leakage onto high voltage components and with minimal cost and complexity.